Hi El Nino,
Trying to remember back to the good old days when I used the MXT and mostly the M6. I used that 8x6 SEF coil for awhile. It did good, but eventually, I went back to the 5.3 as it seemed to unmask a bit better and the vdi numbers stayed tighter using the 5.3 over the SEF.
The one thing the 8 x 6 sef has over the eclipse 5.3 is that looks a lot cooler hanging off the end of the machine over the fat 5.3 coil
A pic of the good ol' days April of 2014 my little M6 and 8 x6 sef.
CoRe,Relic & Racers
MXT All Pro & M6
Big Red 440